The construction of the cavea is dated between 367 and 330 BC. This period coincides with the activity of the Olympic champion, Antiochus of Lepreum, who dedicated the proedries (seats of honor) of the cavea, as recorded in the inscriptions preserved on their backrests.

The theatre was originally built without a permanent stage building (skene). This ensured that the propylon of the Thersilion remained visible from the cavea of the theatre. The Thersilion was the assembly hall of the Arcadian League, where the "Ten Thousand" (Myrioi) convened. When the Thersilion was destroyed in 222/3 BC, a stone proskenion was constructed, as required by the more evolved theatrical art of the era.

The cavea of the theatre was divided into three tiers, separated by two diazomata (horizontal passageways). The first tier contained the row of proedries and twenty-one rows of seats, the second tier contained twenty-two rows, and the third tier contained seventeen rows. The first two tiers were divided into nine wedges (kerkides), served by ten stairways, while the uppermost tier had sixteen wedges. Over the centuries, most of the stone seats and stairways were removed, and today only the lower rows of the first tier survive.

The first row of seats across all nine wedges is occupied by the proedries, which are constructed of limestone and form nine extended thrones with backrests and armrests. On their backrests, they bear an inscription stating that their construction was funded by the agonothetes Antiochus, along with the name of one of the nine Arcadian tribes on each throne. In front of the proedries, between the orchestra and the cavea, a stone drain?the "euripos"?still functions today, carrying rainwater away from the theatre area.